Mucociliary transport (MCT) in respiratory systems functions to maintain airways in a reasonably aseptic state and to protect underlying cells against the adverse effects of inhaled material by transporting foreign particles out of the system. We propose to study this process using a series of functional "models" of the lung mucociliary epithelium isolated from the newt, Taricha granulosa. These models include in order of increasing complexity, 1) populations of highly coupled, isolated, demembranated ciliary axonemes, 2) populations of isolated, coordinted ciliary tufts, 3) populations of living ciliated cells dissociated from the epithelium and 4) patches of the isolated mucociliary epithelium. We have shown previosly that our preparations of ciliary axonemes are the most highly active of those isolated to date and that they respond in a biphasic manner to variations in MgATP and temperature. We have hypoithesized that the beat frequency of these axonemes is controlled by a two state mechanism mediated by the latency of outer arm dynein. We will test this hypotehsis further by determining: 1) whether the biphasic beat frequency response is accompanined by parallel changes in ATPase activity; 2) whether the biphasic response can be localized to the outer arms through comparisons of the best frequencies and ATPase activity of chemically dissected and reconstituted axonemes with those of normal axonemes; 3) whether outer arm dynein isolated from these axonemes does in fact exhibit latency; 4) whether axonemes fixed under conditions favoring each of the hypothesized states exhibit differences in ultra structure; 5) whether the behavior of isolated axonemes is present and/or modified in progressively more complex models. It is hoped that a better understanding of the mechanism(s) controlling ciliary beat frequency will lead to ways of stimulating this process when it is impaired, and of directly evaluating the mode of action of environmental, hormonal and pharmacological agents.